[Viscoelasticity-based treatment of bleeding injuries]

[Viscoelasticity-based point of care coagulation diagnostics in the context of resuscitation room management of severely injured and bleeding trauma patients : Diagnostics and treatment of trauma-induced coagulopathy]

Uncontrolled bleeding with associated trauma-induced coagulopathy (TIC) remains the leading cause of preventable death after severe trauma. Meanwhile, TIC is recognized as a separate clinical entity with substantial impact on downstream morbidity and mortality. In clinical practice severely injured and bleeding patients are often still being treated according to established damage control surgery (DCS) procedures with surgical bleeding control and empirical transfusion of classical blood products in predefined ratios in the sense of damage control resuscitation (DCR); however, algorithms are also available, which have been constructed from established viscoelasticity-based point of care (POC) diagnostic procedures and target value-oriented treatments. The latter enables a timely qualitative assessment of coagulation function from whole blood at bedside and provides rapid and clinically useful information on the presence, development and dynamics of the coagulation disorder. The early implementation of viscoelasticity-based POC procedures in the context of resuscitation room management of severely injured and bleeding patients was uniformly associated with reductions in potentially harmful blood products, especially overtransfusions, and an overall improvement in outcome including survival. The present article reviews the clinical questions around the use of viscoelasticity-based procedures as well as recommendations for the early and acute management of bleeding trauma patients taking the current literature into account.

Operability of a Resonance-Based Viscoelastic Haemostatic Analyzer in the High-Vibration Environment of Air Medical Transport

Trauma and bleeding are associated with a high mortality, and most of these deaths occur early after injury. Viscoelastic haemostatic tests have gained increasing importance in goal-directed transfusion and bleeding management. A new generation of small-sized and thus portable ultrasound-based viscoelastic analysers have been introduced in clinical practice. We questioned whether a promising candidate can be used in emergency helicopters, with a focus on the susceptibility to vibration stress. We investigated whether the high vibration environment of an emergency helicopter would affect the operability of an ultrasound-based viscoelastic analyser and would yield reproducible results in flight and on the ground. We drew blood from 27 healthy volunteers and performed simultaneous analyses on two TEG 6s. Each measurement was performed in-flight on board an Airbus H135 emergency helicopter and was repeated on the ground, close to the flight area. Results from both measurements were compared, and the recorded tracings and numeric results were analysed for artifacts. Vibratometric measurements were performed throughout the flight in order to quantify changes in the magnitude and character of vibrations in different phases of helicopter operation. The high vibration environment was associated with the presence of artifacts in all recorded tracings. There were significant differences in citrated Kaolin + Heparinase measurements in-flight and on the ground. All other assays increased in variability but did not show significant differences between the two time points. We observed numerous artifacts in viscoelastic measurements that were performed in flight. Some parameters that were obtained from the same sample showed significant differences between in-flight and on-ground measurements. Performing resonance-based viscoelastic tests in helicopter medical service is prone to artifacts. However, a 10 min delay between initiation of measurement and take-off might produce more reliable results.

Point-of-Care diagnostics of coagulation in the management of bleeding and transfusion in trauma patients

PURPOSE OF REVIEW

Trauma-associated bleeding and coagulopathy require timely identification, prevention, and effective treatment. The present review summarizes the recent literature around point-of-care (POC) coagulation tests, their usefulness in the management of trauma-induced coagulopathy (TIC), their impact on trauma patient outcomes, and the requirement of quality assurance.

RECENT FINDINGS

Best practice algorithms to manage TIC have been compiled in the 2019 European Guideline on the management of major bleeding and coagulopathy after trauma. Evidence supports the use of goal-directed approaches to manage TIC. POC coagulation tests can accelerate and tailor individualized therapies. Recent findings emphasize: the time sparing of POC tests in prehospital settings and the validity of POC measurements in extreme environments; the potential scalability of POC-guided TIC algorithms in burn injuries and the pediatric population; the need for careful considerations of strategies to monitor and reverse the effects of direct oral anticoagulants in major trauma.

SUMMARY

In contrast to an abundance of reviews and practical approaches to POC coagulation management in trauma patients, there is a scarcity of research in the field and large-scale clinical trials are urgently needed. The paneuropean multicenter trial Implementing Treatment Algorithms for the Correction of Trauma Induced Coagulopathy (iTACTIC) will inform on the potential of viscoelastic tests to augment transfusion protocols for better patient outcomes.

[Hypovolemic and hemorrhagic shock]

The term "shock" refers to a life-threatening circulatory failure caused by an imbalance between the supply and demand of cellular oxygen. Hypovolemic shock is characterized by a reduction of intravascular volume and a subsequent reduction in preload. The body compensates the loss of volume by increasing the stroke volume, heart frequency, oxygen extraction rate, and later by an increased concentration of 2,3-diphosphoglycerate with a rightward shift of the oxygen dissociation curve. Hypovolemic hemorrhagic shock impairs the macrocirculation and microcirculation and therefore affects many organ systems (e.g. kidneys, endocrine system and endothelium). For further identification of a state of shock caused by bleeding, vital functions, coagulation tests and hematopoietic procedures are implemented. Every hospital should be in possession of a specific protocol for massive transfusions. The differentiated systemic treatment of bleeding consists of maintenance of an adequate homeostasis and the administration of blood products and coagulation factors.